# Basics of Number System for Competitive Exams

Basics of Number System for Competitive Exams. Number system is the way of writing numbers. Numerals or symbols are represented as a number depending upon the number system. Binary, Octal, Decimal, Hexadecimal, etc. are some popular number systems.

### Decimal Number System

Decimal number system is the most commonly used and also called the Hindu-Arabic number system.

There are total ten digits (0to 9) used in the decimal number system. So it is a base 10 number system.

Two types of values of a digit in a number:
(1) Face Value – Face Value is the value of the digit itself.
(2) Place Value
– Place value depends upon the position of the digit in the number.

Every place in a number is 10 times more to the immediate right place.

#### Representation of a Number

(1) Standard Form:
Example: 1234.5678

(2) Expanded Form:
Example: 1000+200+30+4+0.5+0.06+0.007+0.0008

(3) Word Form
Example: One thousand two hundred thirty four and (point) five thousand six hundred seventy eight ten thousandth

Mathematics